1. Field of the Invention
The present invention relates generally to a data read apparatus for reading out data which is stored in a nonvolatile memory, a data read method, and a storage medium storing a data read program.
2. Description of the Related Art
In general, a flash memory, which is a nonvolatile memory, is used as a memory of an electronic device such as a mobile terminal. FAT (File Allocation Table) information is necessary for exactly accessing data of a file stored in this flash memory.
For example, methods (1) and (2) to be described below are thought as methods of managing data of the flash memory.
(1) A flash ROM management method is thought (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2000-276402). In this method, read/write of data is managed by forming, with respect to each of sectors which are formed as blocks in a flash memory, a storage area of management information such as a logical sector number corresponding to a storage position of each file in the sector, and information indicating, for example, that the sector is in use or unused. Thereby, a data read/write unit in the flash memory can be managed by making the data read/write unit smaller than a data erase unit.
(2) A flash memory driving method is thought (see, for example, Jpn. Pat. Appln. KOKAI Publication No. H09-097206). In this method, a cache memory is provided at a front stage of a flash memory. The cache memory has a capacity for one sector that is formed as a block in the flash memory. By executing write/read access to the sector which is entered in this cache memory, the substantial number of times of write of the flash memory can be reduced. In the meantime, if a target sector of write/read is not entered in the cache memory, read is directly executed on the flash memory, and write is executed on the cache memory after entering this sector in the cache memory.